JP7593797B2 - Analysis device, analysis system, and analysis method - Google Patents

Description

The embodiments disclosed in this specification and the drawings relate to an analysis device, an analysis system, and an analysis method.

It is important for doctors to know what state plaque formed on blood vessel walls will be in the future in order to develop treatment strategies for vascular diseases. In particular, it is extremely important for doctors to know whether plaque will rupture and cause acute coronary syndrome, which would block the coronary artery, in order to improve the patient's life prognosis.

In recent years, the shear stress (WSS (Wall Shear Stress)) acting on plaque formed on the walls of blood vessels such as coronary arteries has been attracting attention as an index for predicting whether plaque will grow. For example, based on the size of the WSS, it is possible to predict whether plaque will grow in the relatively near future (e.g., six months or one year from now) from the current size of the plaque. This WSS is calculated, for example, by extracting the shape of the patient's blood vessels, including plaque and calcification, from medical image data such as CT (Computed Tomography) image data, and using the extracted blood vessel shape to perform various simulations, such as finite element simulations and simulations using equivalent circuit models.

U.S. Pat. No. 8,734,356 U.S. Pat. No. 1,017,0206 US Patent Application Publication No. 2020/0126219

One of the problems that the embodiments disclosed in this specification and the drawings attempt to solve is to predict the state of plaque in the relatively distant future (e.g., several years from now, such as two years from now). However, the problems that the embodiments disclosed in this specification and the drawings attempt to solve are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described below can also be positioned as other problems.

The analysis device according to the embodiment includes an extraction unit, a calculation unit, a prediction unit, and a display control unit. The extraction unit extracts the shape of the subject's blood vessel and the shape of the plaque formed in the blood vessel from medical image data. The calculation unit calculates a mechanical index for the plaque at a first time point based on the shape of the blood vessel and the shape of the plaque at the first time point while successively changing the first time point. The prediction unit predicts the shape of the plaque at a second time point following the first time point based on the mechanical index at the first time point. The display control unit causes the display unit to display the predicted shape of the plaque at the second time point when the plaque is in a specific state.

FIG. 1 is a diagram illustrating an example of a configuration of an analysis system and an analysis device according to the first embodiment. FIG. 2 is a flowchart illustrating an example of the flow of an analysis process executed by the analysis device according to the first embodiment. FIG. 3 is a diagram illustrating an example of a process executed by the analysis device according to the first embodiment. FIG. 4 is a diagram illustrating an example of a process executed by the analysis device according to the first embodiment. FIG. 5 is a diagram illustrating an example of a process executed by the analysis device according to the first embodiment. FIG. 6 is a diagram illustrating an example of a process executed by the analysis device according to the first embodiment. FIG. 7 is a flowchart illustrating an example of a flow of an analysis process executed by an analysis device according to a first modification of the first embodiment. FIG. 8 is a diagram for explaining an example of processing executed by an analysis device according to the second modification of the first embodiment. FIG. 9 is a diagram for explaining an example of processing executed by an analysis device according to the second modification of the first embodiment. FIG. 10 is a diagram illustrating an example of a process executed by the analysis device according to the second embodiment. FIG. 11 is a diagram illustrating an example of a process executed by the analysis device according to the third embodiment. FIG. 12 is a diagram illustrating an example of a process executed by the analysis device according to the fourth embodiment. FIG. 13 is a diagram illustrating an example of a process executed by the analysis device according to the fourth embodiment. FIG. 14 is a diagram illustrating an example of a process executed by the analysis device according to the fifth embodiment. FIG. 15 is a diagram illustrating an example of a process executed by the analysis device according to the sixth embodiment. FIG. 16 is a diagram illustrating an example of a process executed by the analysis device according to the seventh embodiment.

Below, each embodiment and each modified example of the analysis device, analysis system, and analysis method will be described in detail with reference to the drawings. Note that the embodiments can be combined with conventional technology, other embodiments, or other modified examples to the extent that no contradictions arise in the content. Similarly, the modified examples can be combined with conventional technology, other embodiments, or other modified examples to the extent that no contradictions arise in the content. In addition, in the following description, similar components are given common reference symbols, and duplicate descriptions may be omitted.

(First embodiment)
Fig. 1 is a diagram showing an example of the configuration of an analysis system 100 and an analysis device 150 according to the first embodiment. For example, as shown in Fig. 1, the analysis system 100 according to the first embodiment includes an X-ray CT (Computed Tomography) device 110, a medical image storage device 120, an electronic medical record system 130, a medical information display device 140, and an analysis device 150. Here, the X-ray CT device 110, the medical image storage device 120, the electronic medical record system 130, the medical information display device 140, and the analysis device 150 are communicatively connected via a network 160.

In addition to the X-ray CT device 110, the analysis system 100 may further include other medical image diagnostic devices such as a Magnetic Resonance Imaging (MRI) device, an ultrasound diagnostic device, a Positron Emission Tomography (PET) device, and a Single Photon Emission Computed Tomography (SPECT) device. In addition to the electronic medical record system 130, the analysis system 100 may further include other systems such as a Hospital Information System (HIS) and a Radiology Information System (RIS).

The X-ray CT device 110 generates CT image data related to a subject. As shown in FIG. 1, the X-ray CT device 110 includes a processing circuit 111. The processing circuit 111 is realized, for example, by a processor. The processing circuit 111 includes a generating function 111a. Here, for example, the generating function 111a, which is a component of the processing circuit 111 shown in FIG. 1, is stored in a storage circuit included in the X-ray CT device 110 in the form of a program executable by a computer. The processing circuit 111 reads the program from the storage circuit and executes the read program to realize the generating function 111a corresponding to the program. In other words, the processing circuit 111 in a state in which the program has been read has the generating function 111a shown in the processing circuit 111 in FIG. 1. The generating function 111a is an example of a generating unit.

The X-ray CT device 110 collects projection data representing the distribution of X-rays that have passed through the subject by rotating the X-ray tube and X-ray detector on a circular orbit that surrounds the subject. The generation function 111a of the X-ray CT device 110 then generates CT image data based on the collected projection data. For example, the generation function 111a generates two-dimensional or three-dimensional CT image data 152a that depicts the subject's blood vessels and plaque formed on the blood vessel walls. For example, the CT image data 152a depicts coronary arteries as an example of blood vessels. Note that the blood vessels depicted in the CT image data 152a may be blood vessels other than coronary arteries.

In this embodiment, the CT image data 152a is CT image data captured at time _T0 by the X-ray CT device 110. Therefore, the blood vessels and plaque depicted in the CT image data _152a are the blood vessels and plaque at time _T0 .

Then, the X-ray CT device 110 transmits the CT image data 152a to the medical image storage device 120 and the analysis device 150 via the network 160. The CT image data 152a is an example of medical image data.

The medical image storage device 120 stores various medical image data related to subjects. Specifically, the medical image storage device 120 acquires CT image data from the X-ray CT device 110 via the network 160, and stores the acquired CT image data in a memory circuit provided in the medical image storage device 120. For example, the medical image storage device 120 is realized by a computer device such as a server or a workstation. Also, for example, the medical image storage device 120 is realized by a PACS (Picture Archiving and Communication System) or the like, and stores CT image data in a format compliant with DICOM (Digital Imaging and Communications in Medicine).

The electronic medical record system 130 stores various medical data related to the subject's medical records and patient information. Specifically, the electronic medical record system 130 generates medical data related to the subject or acquires the medical data from other devices via the network 160, and stores the acquired medical data in a memory circuit provided in the electronic medical record system 130. For example, the electronic medical record system 130 is realized by computer equipment such as a server or a workstation.

The medical information display device 140 displays various medical information related to the subject. Specifically, the medical information display device 140 acquires medical information such as CT image data and image processing results from the analysis device 150 via the network 160, and displays the acquired medical information on a display provided in the medical information display device 140. For example, the medical information display device 140 is realized by a computer device such as a workstation, a personal computer, or a tablet terminal.

The analysis device 150 performs various analyses and various image processing on medical image data such as CT image data. Specifically, the analysis device 150 acquires CT image data from the X-ray CT device 110 or the medical image storage device 120 via the network 160, and performs various analyses and various image processing on the acquired CT image data. For example, the analysis device 150 is realized by computer equipment such as a server or a workstation.

As shown in FIG. 1, the analysis device 150 includes a network (NW) interface 151, a memory circuit 152, an input interface 153, a display 154, and a processing circuit 155.

The NW interface 151 controls the transmission and communication of various data sent and received between the analysis device 150 and other devices or the electronic medical record system 130 connected to the analysis device 150 via the network 160. Specifically, the NW interface 151 is connected to the processing circuit 155, and transmits data received from other devices to the processing circuit 155, or transmits data received from the processing circuit 155 to other devices or the electronic medical record system 130. For example, the NW interface 151 is realized by a network card, a network adapter, a NIC (Network Interface Controller), etc.

The memory circuitry 152 stores various data and various programs. Specifically, the memory circuitry 152 is connected to the processing circuitry 155 and stores various data under the control of the processing circuitry 155. In addition, the data stored in the memory circuitry 152 is acquired (read) by the processing circuitry 155. For example, the memory circuitry 152 is realized by a semiconductor memory element such as a random access memory (RAM) or a flash memory, a hard disk, an optical disk, etc.

The input interface 153 accepts input operations of various instructions and various information from the user of the analysis system 100. Specifically, the input interface 153 is connected to the processing circuit 155, converts the input operation received from the user into an electrical signal, and transmits it to the processing circuit 155. For example, the input interface 153 is realized by a trackball, a switch button, a mouse, a keyboard, a touch pad that performs an input operation by touching the operation surface, a touch screen in which a display screen and a touch pad are integrated, a non-contact input interface using an optical sensor, and a voice input interface. Note that in this specification, the input interface 153 is not limited to only those that have physical operation parts such as a mouse and a keyboard. For example, an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the analysis device 150 and transmits this electrical signal to the processing circuit 155 is also included as an example of the input interface 153. Such a processing circuit is realized, for example, by a processor. The input interface 153 is an example of a reception unit.

The display 154 displays various images, various information, and various data. Specifically, the display 154 is connected to the processing circuit 155, and displays images, various information, and various data based on various image data received from the processing circuit 155. For example, the display 154 is realized by a liquid crystal monitor, a CRT (Cathode Ray Tube) monitor, a touch panel, etc. The display 154 is an example of a display unit.

The processing circuitry 155 controls the entire analysis device 150. For example, the processing circuitry 155 performs various processes in response to input operations received from a user via the input interface 153. For example, the processing circuitry 155 receives data transmitted by another device via the NW interface 151 and stores the received data in the memory circuitry 152. For example, an acquisition function 155a of the processing circuitry 155, which will be described later, receives (acquires) CT image data 152a transmitted from the X-ray CT device 110 via the NW interface 151 and stores the received CT image data 152a in the memory circuitry 152 as shown in FIG. 1. For example, the processing circuitry 155 controls the NW interface 151 to transmit data acquired from the memory circuitry 152 to another device or the electronic medical record system 130. As a result, the NW interface 151 transmits this data to the other device or the electronic medical record system. For example, the processing circuitry 155 displays the data acquired from the memory circuitry 152 on the display 154. The processing circuit 155 is realized, for example, by a processor.

A configuration example of the analysis system 100 and analysis device 150 according to this embodiment has been described above. For example, the analysis system 100 and analysis device 150 according to this embodiment are installed in medical facilities such as hospitals and clinics, and support the diagnosis and formulation of treatment plans for diseases of blood vessels such as coronary arteries performed by users such as doctors.

For example, the shear stress (WSS (Wall Shear Stress)) applied to plaque formed on the vascular wall of a blood vessel such as a coronary artery is generally used as an index for predicting whether the plaque will grow. In the following explanation, "shear stress applied to plaque" is referred to as "WSS applied to plaque." For example, based on the size of the WSS applied to the plaque, it is possible to predict whether the plaque will grow in the relatively near future (e.g., six months or one year from now) from the current size of the plaque. However, it is difficult to predict the state of the plaque in the relatively distant future (e.g., several years from now, such as two years from now).

For this reason, the analysis system 100 and analysis device 150 according to this embodiment are configured to be able to predict the state of plaque in the relatively distant future, as described below.

For example, as shown in FIG. 1, the processing circuit 155 includes an acquisition function 155a, an extraction function 155b, a calculation function 155c, a prediction function 155d, and a display control function 155e. The acquisition function 155a is an example of an acquisition unit. The extraction function 155b is an example of an extraction unit. The calculation function 155c is an example of a calculation unit. The prediction function 155d is an example of a prediction unit. The display control function 155e is an example of a display control unit.

Here, for example, each of the processing functions of the processing circuitry 155 shown in FIG. 1, namely, the acquisition function 155a, the extraction function 155b, the calculation function 155c, the prediction function 155d, and the display control function 155e, are stored in the memory circuitry 152 in the form of a program executable by a computer. The processing circuitry 155 reads each program from the memory circuitry 152, and executes each read program to realize the function corresponding to each program. In other words, the processing circuitry 155 in a state in which each program has been read has each function shown in the processing circuitry 155 in FIG. 1.

Figure 2 is a flowchart showing an example of the flow of the analysis process executed by the analysis device 150 according to the first embodiment. The analysis process is a process in which the CT image data 152a is analyzed to obtain a prediction result of the state of plaque in the relatively distant future. For example, the analysis process is executed when the processing circuitry 155 receives an instruction to execute the analysis process from a user such as a doctor via the input interface 153 while the memory circuitry 152 stores the CT image data 152a.

2, the acquisition function 155a sets a variable N to an initial value of "0" (step S101). Then, the acquisition function 155a acquires the CT image data 152a at time _T0 from the memory circuitry 152 (step S102).

Then, the extraction function 155b extracts the shape of the blood vessel at time _T0 and the shape of the plaque at time _T0 from the CT image data 152a (step S103). Fig. 3 is a diagram for explaining an example of a process executed by the analysis device 150 according to the first embodiment. For example, in step S103, as shown in Fig. 3, the extraction function 155b extracts the shape of the blood vessel 11 at time _T0 and the shape of the plaque 12 at time _T0 from the CT image data 152a.

Then, the calculation function 155c calculates the WSS applied to the plaque 12 at time _{T.sub.N based on the shape of the blood vessel 11 at time T.sub.0 and the shape of the plaque 12 at time T.sub.N (step S104). For example, when the initial value "0" is set to the variable N, in step S104, the calculation function 155c calculates the WSS applied to the plaque 12 at time T.sub.0 based on} the shape of the blood vessel 11 at time _T.sub.0 and the shape of the plaque 12 at time _T.sub.0 . The WSS applied to the plaque 12 is an example of shear stress and is also an example of a mechanical index indicating such shear stress.

Here, various methods for calculating the WSS are known as publicly known techniques. In step S104, the calculation function 155c calculates the WSS on the plaque 12 using such publicly known techniques. For example, the values of various parameters such as the amount of blood flowing into the blood vessel 11 per unit time, the flow rate of the blood flowing into the blood vessel 11, the amount of blood flowing out of the blood vessel 11 per unit time, the flow rate of the blood flowing out of the blood vessel 11, the cross-sectional area of the blood vessel at the inflow position of the blood vessel 11, the cross-sectional area of the blood vessel at the outflow position of the blood vessel 11, the blood pressure at the inflow position of the blood vessel 11, and the blood pressure at the outflow position of the blood vessel 11 are predetermined. Then, the calculation function 155c performs various simulations to calculate the WSS on the plaque 12 using these various parameters. As a result, the WSS on the plaque 12 is calculated. For example, the calculation function 155c uses various parameters to execute a finite element simulation of blood flow or a simulation using an equivalent circuit model based on the shape of the blood vessel 11 and the shape of the plaque 12, thereby calculating the WSS applied to the plaque 12. Note that the amount of blood flowing into the blood vessel 11 per unit time, the flow speed of the blood flowing into the blood vessel 11, and the pressure of the blood at the inflow position of the blood vessel 11 are parameters related to the blood flowing into the blood vessel 11. Also, the amount of blood flowing out of the blood vessel 11 per unit time, the flow speed of the blood flowing out of the blood vessel 11, and the pressure of the blood at the outflow position of the blood vessel 11 are parameters related to the blood flowing out of the blood vessel 11.

Then, the prediction function 155d predicts the shape of the plaque 12 at time T _N+1 based on the WSS of the plaque 12 at time T _N (step S105). Here, for example, the time interval (time step) between time T _N and the time T _N+1 next to time T _N is, for example, one month. That is, in step S105, the prediction function 155d predicts the shape of the plaque 12 at time T _N+1 , which is one month after time T _N , based on the WSS of the plaque 12 at time T _N. More specifically, for example, when the initial value "0" is set to the variable N, the prediction function 155d predicts the shape of the plaque 12 at time T ₁ , which is one month after time T ₀ , based on the WSS of the plaque 12 at time T ₀ .

A specific example of the process executed by the prediction function 155d in step S105 will be described. Fig. 4 is a diagram for explaining an example of the process executed by the analysis device 150 according to the first embodiment. In Fig. 4, the plaque 12 at time T _N is indicated by a dashed line, and the plaque 12 at time T _N+1 is indicated by a solid line.

In step S105, the prediction function 155d first determines whether or not the size of the WSS on the plaque 12 at the time T _N is below the first threshold value α. Here, for example, the size of the WSS being below the first threshold value α means that the size of the WSS is less than the first threshold value α. When the size of the WSS is below the first threshold value α, it is considered that the plaque 12 grows and becomes larger. Therefore, when the size of the WSS is below the first threshold value α, as shown in FIG. 4, the prediction function 155d predicts the shape of the plaque 12 at the time T _{N +1 by enlarging the shape of the plaque 12 by a predetermined size from each of the multiple positions 12a in the normal direction of each of the multiple positions 12a on the surface of the plaque 12 at the time T N.} Here, the predetermined size is, for example, 0.01 mm. In this way, the prediction function 155d predicts the shape of the plaque 12 at the time T _N+1 by enlarging the shape of the plaque 12 at the time T _N. That is, the prediction function 155d predicts the shape of the plaque 12 at time T _N+1 by making the shape of the plaque 12 at time T _N+1 larger than the shape of the plaque 12 at time T _N .

It is also considered that the plaque 12 grows and becomes larger when the magnitude of the WSS on the plaque 12 falls below the first threshold value α and the maximum value of the difference in WSS in one pulse exceeds the second threshold value β. Therefore, in step S105, the prediction function 155d may determine whether or not the magnitude of the WSS on the plaque 12 at time T _N falls below the first threshold value α and the maximum value of the difference in WSS in one pulse exceeds the second threshold value β. The maximum value of the difference in WSS in one pulse here is, for example, the difference between the maximum and minimum values of WSS in one pulse. Moreover, the maximum value of the difference in WSS exceeds the second threshold value β means that the maximum value of the difference in WSS is greater than the second threshold value β. In this case, when the magnitude of the WSS on the plaque 12 at time T _N falls below the first threshold value α and the maximum value of the difference in WSS in one beat exceeds the second threshold value β, the prediction function 155d may predict the shape of the plaque 12 at time T _N+1 by enlarging the shape of the plaque 12 at time T _N , as described above.

In addition, when the size of the WSS falls below the first threshold value α, or when the size of the WSS falls below the first threshold value α and the maximum value of the difference in WSS in one beat exceeds the second threshold value β, the prediction function 155d may enlarge the shape of the plaque 12 at the time point T _N by a method other than the method described above.

For example, the prediction function 155d may increase the shape of the plaque 12 at the time T 1 _N by increasing the volume of the plaque 12 at the time T 1 _N by 1%. In this case, the prediction function 155d may increase the shape of the plaque 12 by a constant rate in the normal direction of the surface of the plaque 12 in each region not in contact with the blood vessel 11.

Furthermore, for example, the prediction function 155d may enlarge the shape of the plaque 12 by a size according to the size of the WSS from each of the multiple positions 12a in the normal direction of each of the multiple positions 12a on the surface of _the plaque 12 at the time point T to N. Here, the "size according to the size of the WSS" is, for example, "0.01 x C1 x 1/P" mm when the size of the WSS is "P", where "C1" is a coefficient with a positive value.

Returning to the explanation of FIG. 2, the prediction function 155d sets the physical properties of the plaque 12 at time T _{N +1} based on the WSS of the plaque 12 at time T N (step S106).

A specific example of the process executed in step S106 will be described. For example, if the size of the WSS on the plaque 12 at time T - _N is equal to or greater than the first threshold value α, it is considered that a fibrous cap develops on the surface of the plaque 12. For example, the plaque 12 is formed of multiple components including a fibrous cap, calcium, and lipids. Therefore, if the size of the WSS is equal to or greater than the first threshold value α, it is considered that the ratio of the fibrous cap to the multiple components increases. The fibrous cap is a hard component compared to lipids. Therefore, when the ratio of the fibrous cap to the multiple components increases, the plaque 12 becomes hard.

Therefore, in step S106, when the magnitude of WSS is equal to or greater than the first threshold value α, the prediction function 155d sets the physical properties of the plaque 12 at time point T _N+1 so that the plaque 12 at time point T _N+1 is harder than the plaque 12 at time point T _N. For example, the prediction function 155d sets _the physical properties of the plaque 12 at time point T _N+1 by changing the physical properties of the plaque 12 at time point T _N so that the ratio of the fibrous cap to all components constituting the plaque 12 at time point T _N+1 is greater than the ratio of the fibrous cap to all components constituting the plaque 12 at time point T N.

For example, the prediction function 155d sets the physical properties of the plaque 12 at time T _{N+1 by changing a predetermined number of lipids among all lipids contained in the surface of the plaque 12 at time T N to a fibrous cap. Note that the prediction function 155d may set the physical properties of the plaque 12 at time T N+1 by dividing} the surface of the plaque 12 at time T _N into a plurality of regions, randomly selecting a region from the plurality of regions, and changing the components contained in the selected region to a fibrous cap.

Also, in step S106, the prediction function 155d determines whether the magnitude of the WSS on the plaque 12 at the time T 1 _N is equal to or less than a third threshold value γ, which is smaller than the first threshold value α. If the magnitude of the WSS is equal to or less than the third threshold value γ, it is considered that the plaque 12 will grow to include more lipids. Therefore, if the magnitude of the WSS is equal to or less than the third threshold value γ, it is considered that the ratio of lipids to the multiple components will be large. Lipids are soft components compared to calcium and fibrous caps. Therefore, as the ratio of lipids to the multiple components increases, the plaque 12 will become softer.

Therefore, in step S106, when the size of WSS is equal to or smaller than the third threshold value γ, the prediction function 155d sets the physical properties of the plaque 12 at time point T _N+1 so that the plaque 12 at time point T _N+1 is softer than the plaque 12 at time point T _N. For example, the prediction function 155d sets _the physical properties of the plaque 12 at time point T _N+1 by changing the physical properties of the plaque 12 at time point T _N so that the ratio of lipids to all components constituting the plaque 12 at time point T _N+1 is higher than the ratio of lipids to all components constituting the plaque 12 at time point T N.

For example, the prediction function 155d sets the physical properties of the plaque 12 at time T _N+1 by changing a predetermined number of fibrous caps and calcium out of all of the fibrous caps and calcium contained in the plaque 12 at time T _N to lipids. Note that the prediction function 155d may set the physical properties of the plaque 12 at time T _N+1 by dividing the plaque 12 at time T _N into a plurality of regions, randomly selecting a region from the plurality of regions, and changing the components contained in the selected region to lipids.

Then, the calculation function 155c determines whether or not the plaque 12 will be in a specific state at the time point T _N+1 (step S107).

A specific example of the process executed by the calculation function 155c in step S107 will be described. FIG. 5 is a diagram for explaining an example of the process executed by the analysis device 150 according to the first embodiment. For example, in step S107, as shown in FIG. 5, the calculation function 155c determines whether the growth of the plaque 12 has converged at the time T _N+1 . For example, the calculation function 155c calculates the distance between each of the multiple positions 12a of the plaque 12 at the time T _N and each of the multiple positions 12a of the plaque 12 at the time T _N+1 . This calculates multiple distances. Then, the calculation function 155c calculates the average value of the multiple distances. Then, the calculation function 155c determines whether the average value is equal to or less than a predetermined threshold value δ. If the average value is equal to or less than the predetermined threshold value δ, the calculation function 155c determines that the growth of the plaque 12 has converged at the time T _N+1 . Furthermore, if the average value is greater than the predetermined threshold value δ, the calculation function 155c determines that the growth of the plaque 12 has not converged at the time point T _N+1 .

In step S107, the calculation function 155c may determine that the growth of the plaque 12 has converged if the magnitude of the WSS on the plaque 12 at time T 1 _N is equal to or greater than a threshold value (e.g., the first threshold value α). On the other hand, the calculation function 155c may determine that the growth of the plaque 12 has not converged if the magnitude of the WSS on the plaque 12 at time T 1 _N is below a threshold value (e.g., the first threshold value α). In addition, in step S107, the calculation function 155c may determine that the growth of the plaque 12 has converged if the maximum value of the difference in WSS in one beat is equal to or less than the second threshold value β. On the other hand, the calculation function 155c may determine that the growth of the plaque 12 has not converged if the maximum value of the difference in WSS in one beat exceeds the second threshold value β.

If the plaque 12 is not in a specific state at time T _N+1 (step S107: No), that is, if the growth of the plaque 12 has not converged at time T _N+1 , the calculation function 155c increments the value of the variable N by one (step S108). Here, the calculation function 155c increments the value of the variable N by one to derive a new time T _N (this N is the N before being incremented by one) that is the next time of the time T _N (this N is the N after being incremented by one). For example, if the value of the variable N is "0", the calculation function 155c increments the value of the variable N by one to derive a time T ₁ that is the next time of the time T _0. Similarly, if the value of the variable N is "k (k is an integer equal to or greater than 1)", the calculation function 155c increments the value of the variable N by one to derive a time T _k+1 that is the next time of the time T _k . Each time point after time point _T0 is an example of a first time point, and the time point next to such a first time point is an example of a second time point.

Then, the calculation function 155c returns from step S108 to step S104. Then, the calculation function 155c and the prediction function 155d again execute the processes from step S104 to step S107.

In addition, when returning from step S108 to step S104, in step S104, the calculation function 155c calculates the WSS for the plaque 12 at time T _N using the shape of the blood vessel at time T ₀ and the shape of the plaque 12 at time T _N predicted in step S105.

Therefore, until the plaque 12 reaches a specific state (step S107: Yes), the value of the variable N is repeatedly incremented by one in step S108, and each time the value of the variable N is incremented by one, the processes from step S104 to step S107 are executed. For example, each time the value of the variable N is incremented by one, the processes from step S104 to step S107 are executed until the growth of the plaque 12 converges.

Furthermore, in the first embodiment, the prediction function 155d predicts the shape of the plaque 12 at the next time point T _k+1 after time point T _k based on the calculated WSS each time the WSS of the plaque 12 is calculated at time point T _k , until the growth of the plaque 12 converges.

Fig. 6 is a diagram for explaining an example of processing executed by the analysis device 150 according to the first embodiment. With reference to Fig. 6, an example of processing executed by the display control function 155e when the plaque 12 reaches a specific state at time T _N+1 (step S107: Yes), i.e., when the growth of the plaque 12 converges at time T _N+1, will be described. In this case (step S107: Yes), the display control function 155e causes the display 154 to display the shape of the plaque 12 at time T _N+1 predicted in step S105 (step S109), as shown in Fig. 6.

That is, in step S109, the display control function 155e causes the display 154 to display the shape of the plaque 12 at the time T _N+1 when the plaque 12 reaches a specific state (the time when the plaque 12 reaches a specific state). Specifically, the display control function 155e causes the display 154 to display the shape of the plaque 12 at the time T _N+1 when the growth of the plaque 12 has converged. Then, the display control function 155e ends the analysis process.

The analysis device 150 and the analysis system 100 according to the first embodiment have been described above. The analysis device 150 and the analysis system 100 predict the shape of the plaque 12 at time T _N+1 when the plaque 12 reaches a specific state. Specifically, the analysis device 150 and the analysis system 100 predict the shape of the plaque 12 at time T _N+1 when the growth of the plaque 12 has converged. Here, for example, the time T _N+1 is a time several years, such as two years, after time T _0. Therefore, according to the first embodiment, it is possible to predict the state of the plaque 12 in the relatively distant future (e.g., several years).

Furthermore, the analysis device 150 and the analysis system 100 display the shape of the plaque 12 at the time T _N+1 when the plaque 12 reaches a specific state. Specifically, the analysis device 150 and the analysis system 100 display the shape of the plaque 12 at the time T _N+1 when the growth of the plaque 12 has converged. Therefore, according to the first embodiment, it is possible to allow a user such as a doctor to check the state of the plaque 12 in the relatively distant future. As a result, it is possible to support the diagnosis and formulation of a treatment plan for a disease of a blood vessel such as a coronary artery performed by a user such as a doctor.

(First Modification of the First Embodiment)
In the above-described first embodiment, a case has been described in which in step S104, the calculation function 155c uses the shape of the blood vessel 11 at time _T0 when calculating the WSS of the plaque 12 at time _T1N . In this manner, in the first embodiment, the shape of the blood vessel 11 is constant and does not change in the analysis process. However, the calculation function 155c may correct the shape of the blood vessel 11. Then, the calculation function 155c may calculate the WSS of the plaque 12 at time _T1N using the corrected shape of the blood vessel 11 at time _T1N .

Therefore, such a modification will be described as a first modification of the first embodiment. Note that in the description of the first modification of the first embodiment, differences from the first embodiment will be mainly described, and a description of configurations similar to those of the first embodiment may be omitted. For example, in the description of the first modification of the first embodiment, configurations similar to those of the first embodiment may be given the same reference numerals, and a description of configurations similar to those of the first embodiment may be omitted.

Figure 7 is a flowchart showing the flow of an example of an analysis process executed by the analysis device 150 according to the first modification of the first embodiment. The analysis process according to the first modification of the first embodiment shown in Figure 7 differs from the analysis process according to the first embodiment shown in Figure 2 in that the processes of steps S121 to S125 are executed between steps S103 and S104, and between steps S108 and S104.

As shown in FIG. 7, after the processing of step S103 or step S108 is executed, the display control function 155e causes the display 154 to display the shape of the blood vessel 11 at time T 1 _N and the shape of the plaque 12 at time T 1 _N (step S121).

Then, the calculation function 155c determines whether or not the input interface 153 has received a correction instruction input by the user to correct the shape of the blood vessel 11 at the time point _T.sub.N (step S122).

If the input interface 153 has not received a correction instruction (step S122: No), the calculation function 155c determines whether or not the input interface 153 has received an instruction of no correction required input by the user, which indicates that correction of the shape of the blood vessel 11 at the time point T _N is not required (step S123). If the input interface 153 has received an instruction of no correction required (step S123: Yes), the calculation function 155c proceeds to step S104 and executes the process of step S104.

In a first modified example of the first embodiment, when the value of the variable N is "0" in step S104, the calculation function 155c calculates the _WSS of the plaque 12 at time T0 based on the shape of the blood vessel 11 at time _T0 and the shape of the plaque 12 at time _T0 . Also, when the value of the variable N is "k (k is an integer of 1 or more)" in step S104, the calculation function 155c calculates the WSS of the plaque 12 at time _TN based on the shape of the blood vessel 11 at time _TN and the shape of the plaque 12 at time _TN . The shape of the blood vessel 11 at time _TN here is, for example, the shape of the blood vessel 11 at time TN _-1 used when the calculation function 155c calculates the WSS of the plaque 12 at time TN _-1 in step S104 or step S125.

Also, if the input interface 153 does not receive an instruction that no correction is required (step S123: No), the calculation function 155c returns to step S122 and executes the processing of step S122 again.

Furthermore, when the input interface 153 receives a correction instruction (step S122: Yes), the calculation function 155c corrects the shape of the blood vessel 11 at the time point _T.sub.N based on the correction instruction (step S124).

Then, the calculation function 155c calculates the WSS for the plaque 12 at the time T _N based on the corrected shape of the blood vessel 11 at the time T _N and the shape of the plaque 12 at the time T _N (step S125). When the process proceeds from step S125 to step S105, the calculation function 155c predicts, in step S105, the shape of the plaque 12 at the time T _N+1 based on the WSS calculated in step S125.

A case where the process returns from step S108 to step S121 in the first modified example of the first embodiment will be described below. In this case, in step S121, the display control function 155e sets the shape of the blood vessel 11 at time T _N-1 used in calculating the WSS of the plaque 12 at time T _N-1 as the shape of the blood vessel 11 at time T _N , and causes the display 154 to display the shape of the blood vessel 11 at time T _N and the shape of the plaque 12 at time T _N.

In the analysis process shown in FIG. 7, the calculation function 155c corrects the shape of the blood vessel 11 at the time T 1 _N used in calculating the WSS. Here, the parameters related to the blood flowing into the blood vessel 11 and the parameters related to the blood flowing out of the blood vessel 11 are also used in calculating the WSS. Therefore, the calculation function 155c may correct the parameters related to the blood flowing into the blood vessel 11 and the parameters related to the blood flowing out of the blood vessel 11 in a manner similar to the method of correcting the shape of the blood vessel 11 at the time T ₁ N. The parameters related to the blood flowing into the blood vessel 11 are an example of a first parameter. Also, the parameters related to the blood flowing out of the blood vessel 11 are an example of a second parameter.

That is, the input interface 153 accepts at least one of an instruction to modify the shape of the blood vessel 11 at the time _T1N , an instruction to modify parameters related to blood flowing into the blood vessel 11, and an instruction to modify parameters related to blood flowing out of the blood vessel 11. Then, the calculation function 155c calculates the WSS for the plaque 12 at the time T1N based on at least one of the shape of the blood vessel 11 at the time _T1N , the parameters related to blood flowing into the blood vessel 11, and the parameters related to blood flowing out of the blood vessel 11 that have been modified based on at least one instruction accepted by the input _interface 153.

The above describes the analysis device 150 and analysis system 100 according to the first modified example of the first embodiment. According to the first modified example of the first embodiment, if the shape of the blood vessel 11 used when calculating the WSS of the plaque 12 is not accurate, the user can correct the shape of the blood vessel 11 to an accurate shape, thereby allowing the WSS to be calculated with high accuracy. Similarly, if the values of various parameters used when calculating the WSS of the plaque 12 are not accurate, the user can correct the parameter values to accurate values, thereby allowing the WSS to be calculated with high accuracy.

(Second Modification of the First Embodiment)
In step S105, the prediction function 155d may predict the shape of the plaque 12 at the time T _N+1 by a method other than the method described in the first embodiment. For example, the plaque 12 is a relatively soft object. For this reason, it is considered that the plaque 12 is deformed by the force (pressure) received from the blood flow. Therefore, when predicting the shape of the plaque 12, the prediction function 155d may deform the plaque 12 based on the force received from the blood flow. Therefore, such a modified example will be described as a second modified example of the first embodiment.

In the description of the second modified example of the first embodiment, differences from the first embodiment will be mainly described, and descriptions of configurations similar to those of the first embodiment may be omitted. For example, in the description of the second modified example of the first embodiment, configurations similar to those of the first embodiment may be given the same reference numerals, and descriptions of configurations similar to those of the first embodiment may be omitted.

A method for predicting the shape of the plaque 12 at time T _{N +1} by the prediction function 155d according to the second modified example of the first embodiment will be described with reference to Fig. 8 and Fig. 9. Fig. 8 and Fig. 9 are diagrams for explaining an example of processing executed by the analysis device 150 according to the second modified example of the first embodiment.

When the magnitude of WSS falls below the first threshold value α, or when it falls below the first threshold value α and the maximum difference in WSS in one pulse exceeds the second threshold value β, the prediction function 155d calculates the angle between the normal direction of each of the multiple positions 12a on the surface of the plaque 12 at the time point T to _N and the direction of blood flow in the blood vessel 11, which is the direction indicated by the arrow 13 shown in Fig. 8. For example, the prediction function 155d calculates the angle for each of the multiple positions 12a in the range of 0 degrees to 180 degrees.

In the example of Figure 8, the angle between the normal direction of the leftmost position 12a in Figure 8 out of the five positions 12a and the direction of blood flow indicated by arrow 13 is 180 degrees. Also, the angle between the normal direction of the middle position 12a in the left-right direction out of the five positions 12a and the direction of blood flow indicated by arrow 13 is 90 degrees. The angle between the normal direction of the rightmost position 12a in Figure 8 out of the five positions 12a and the direction of blood flow indicated by arrow 13 is 0 degrees.

Here, the force that position 12a receives from the blood flow decreases as the angle decreases and increases as the angle increases. Therefore, the growth of the portion of plaque 12 at position 12a is promoted as the angle decreases and inhibited as the angle increases.

9, the prediction function 155d enlarges the shape of the plaque 12 in the normal direction of each of the multiple positions 12a by a size according to the angle. The prediction function 155d then predicts the shape of the plaque 12 obtained in this manner as the shape of the plaque 12 at time T _N+1 . Here, the size according to the angle is, for example, a size that increases as the angle decreases and a size that decreases as the angle increases. Therefore, according to the second modification of the first embodiment, the prediction function 155d can predict how the plaque 12 will be deformed by the force received from the blood flow.

The analysis device 150 and the analysis system 100 according to the second modified example of the first embodiment have been described above. In the second modified example of the first embodiment, as described above, the prediction function 155d predicts the shape of the plaque 12 at time T _N +1 by enlarging the shape of the plaque 12 in the normal direction of each of the multiple positions 12a on the surface of the plaque 12 at time T _N by a size corresponding to the angle between the normal direction of each of the multiple positions 12a and the direction of blood flow in the blood vessel 11. Therefore, according to the second modified example of the first embodiment, as described above, it is possible to predict how the plaque 12 will be deformed by the force received from the blood flow.

Note that the method for predicting how plaque 12 will be deformed by the force from the blood flow is not limited to the above-mentioned method. Therefore, other methods for predicting how plaque 12 will be deformed by the force from the blood flow will be described.

For example, as in the first embodiment, the prediction function 155d enlarges the shape of the plaque 12 by a predetermined size from each of the multiple positions 12a in the normal direction of each of the multiple positions 12a on the surface of the plaque 12 at time T to _N , as shown in FIG.

The prediction function 155d then predicts how the plaque 12 will deform when the pressure of the blood flow is applied to the plaque 12 by using a fluid structure engineering simulation or the like. For example, the prediction function 155d first defines the spatial distribution of the softness of the plaque 12. For example, the prediction function 155d acquires the distribution of the CT value of the plaque 12 from the CT image data 152a. Then, the prediction function 155d defines the spatial distribution of the softness of the plaque 12 based on the distribution of the CT value of the plaque 12.

Then, the prediction function 155d simulates how the plaque 12 will deform based on the magnitude and direction of the pressure that each position 12a of the plaque 12 receives due to the blood flow, the shape of the plaque 12, and the spatial distribution of the softness of the plaque 12, and obtains the shape of the plaque 12 after deformation.

Then, the prediction function 155d predicts the obtained shape of the plaque 12 as the shape of the plaque 12 at time T _N+1 .

Second Embodiment
In the first embodiment, a case has been described in which the analysis device 150 uses the time point at which the growth of the plaque 12 has converged as the time point at which the plaque 12 reaches a specific state. Then, in the first embodiment, a case has been described in which the analysis device 150 predicts the shape of the plaque 12 at the time point at which the growth of the plaque 12 has converged, and displays the predicted shape of the plaque 12. However, the analysis device 150 may use the time point at which the plaque 12 reaches a state that poses a risk to the subject, as the time point at which the plaque 12 reaches a specific state. Then, the analysis device 150 may predict the shape of the plaque 12 at the time point at which the plaque 12 reaches a state that poses a risk to the subject, and display the predicted shape of the plaque 12. Thus, such an embodiment will be described as a second embodiment.

In the description of the second embodiment, differences from the first embodiment will be mainly described, and descriptions of configurations similar to those of the first embodiment may be omitted. For example, in the description of the second embodiment, configurations similar to those of the first embodiment may be given the same reference numerals, and descriptions of configurations similar to those of the first embodiment may be omitted.

Fig. 10 is a diagram for explaining an example of processing executed by the analysis device 150 according to the second embodiment. For example, in the second embodiment, in step S107, the calculation function 155c determines whether or not the plaque 12 will be in a state that poses a risk to the subject at time T _N+1 , as shown in Fig. 10. Specifically, in step S107, the calculation function 155c determines whether or not the plaque 12 will be in a ruptured state at time T _N+1 .

A specific example of the process executed in step S107 will be described. For example, the calculation function 155c calculates the force of the fluid acting on the plaque 12. Then, based on the shape of the plaque 12 and the physical properties of the plaque 12 (e.g., softness), the calculation function 155c determines that the plaque 12 will be in a ruptured state when a force equal to or greater than a certain force is applied to the plaque 12. Furthermore, if the force applied to the plaque 12 is smaller than the certain force, the calculation function 155c determines that the plaque 12 will not be in a ruptured state. Note that the calculation function 155c may use fracture mechanics to determine whether or not the plaque 12 will be in a ruptured state.

The calculation function 155c determines that the plaque 12 will be in a state that poses a risk to the subject by determining that the plaque 12 will be in a ruptured state. The calculation function 155c also determines that the plaque 12 will not be in a state that poses a risk to the subject by determining that the plaque 12 will not be in a ruptured state.

If the plaque 12 is in a state that poses a risk to the subject (step S107: Yes), the display control function 155e proceeds to step S109 and executes the processing of step S109. On the other hand, if the plaque 12 is not in a state that poses a risk to the subject (step S107: No), the calculation function 155c proceeds to step S108 and executes the processing of step S108.

Therefore, in the second embodiment, the calculation function 155c calculates the WSS of the plaque 12 at time _Tk each time the time _Tk is derived until the plaque 12 becomes a state that poses a risk to the subject. Then, the prediction function 155d predicts the shape of the plaque 12 at the time Tk+1 next to the time _Tk based on the calculated WSS each time the WSS of the plaque 12 is calculated at time _Tk until the plaque 12 becomes a state that poses a risk to the subject. Then, the display control function 155e causes the display 154 to display the shape of the plaque 12 at time Tk _{+1 when} the plaque 12 becomes a state that poses a risk to the subject.

Specifically, the calculation function 155c calculates the WSS of the plaque 12 at time _Tk each time a time _Tk is derived until the plaque 12 ruptures. Then, the prediction function 155d predicts the shape of the plaque 12 at the time _Tk+1 next to the time _Tk based on the calculated WSS each time the WSS of the plaque 12 is calculated at time _Tk until the plaque 12 ruptures. Then, the display control function 155e causes the display 154 to display the shape of the plaque 12 at time _Tk+1 when the plaque 12 ruptures.

The above describes the analysis device 150 and analysis system 100 according to the second embodiment. According to the second embodiment, it is possible to predict that in the relatively distant future, the plaque 12 will reach a state where it poses a risk to the subject. It is also possible to predict that in the relatively distant future, the plaque 12 will reach a state where it will rupture.

Furthermore, according to the second embodiment, it is possible to allow a user such as a doctor to confirm that in the relatively distant future, the plaque 12 will be in a state where it poses a risk to the subject. Also, according to the second embodiment, it is possible to allow a user such as a doctor to confirm that in the relatively distant future, the plaque 12 will be in a state where it will rupture. As a result, it is possible to support the diagnosis and formulation of treatment plans for diseases of blood vessels such as coronary arteries, which are performed by users such as doctors.

Third Embodiment
In the above-described second embodiment, a case has been described in which the analysis device 150 uses the time when the plaque 12 becomes in a state where it will rupture as the time when the plaque 12 becomes in a state where it will pose a risk to the subject. Also, in the second embodiment, a case has been described in which the analysis device 150 predicts the shape of the plaque 12 at the time when the plaque 12 becomes in a state where it will rupture, and displays the predicted shape of the plaque 12. However, the analysis device 150 may use the time when the plaque 12 becomes in a state where it will obstruct blood flow in the blood vessel 11 as the time when the plaque 12 becomes in a state where it will obstruct blood flow in the blood vessel 11, as the time when the plaque 12 becomes in a state where it will pose a risk to the subject. Then, the analysis device 150 may predict the shape of the plaque 12 at the time when the plaque 12 becomes in a state where it will obstruct blood flow in the blood vessel 11, and display the predicted shape of the plaque 12. Therefore, such an embodiment will be described as a third embodiment.

Note that in the description of the third embodiment, differences from the first embodiment will be mainly described, and descriptions of configurations similar to those of the first embodiment may be omitted. For example, in the description of the third embodiment, configurations similar to those of the first embodiment may be given the same reference numerals, and descriptions of configurations similar to those of the first embodiment may be omitted.

Fig. 11 is a diagram for explaining an example of processing executed by the analysis device 150 according to the third embodiment. For example, in the third embodiment, in step S107, the calculation function 155c determines whether or not the plaque 12 will be in a state that poses a risk to the subject at time T _N+1 , as shown in Fig. 11. Specifically, in step S107, the calculation function 155c determines whether or not the plaque 12 will be in a state that obstructs blood flow in the blood vessel 11 at time T _N+1 .

A specific example of the process executed in step S107 will be described. For example, the calculation function 155c calculates the fractional flow reserve (FFR) in the blood vessel 11 at time _T.sub.N. For example, the calculation function 155c calculates the FFR using a known technique for calculating the FFR. For example, the calculation function 155c calculates the FFR at time T.sub.N based on the shape of the blood vessel 11 at time _T.sub.0 , the shape of the plaque 12 at time _T.sub.N , parameters related to blood flowing into the blood vessel 11, and parameters related to blood flowing out of the blood vessel ₁₁ .

Then, the calculation function 155c determines whether or not the value of the FFR at the time T _N is less than a predetermined value (e.g., 0.85). If the value of the FFR at the time T _N is less than the predetermined value, the calculation function 155c determines that the plaque 12 will be in a state where it obstructs the blood flow in the blood vessel 11 at the time T N ₊₁ . On the other hand, if the value of the FFR at the time T _N is equal to or greater than the predetermined value, the calculation function 155c determines that the plaque 12 will not be in a state where it obstructs the blood flow in the blood vessel 11 at the time T _N+1 .

The calculation function 155c determines that the plaque 12 will be in a state that poses a risk to the subject by determining that the plaque 12 will be in a state that obstructs the blood flow in the blood vessel 11. The calculation function 155c also determines that the plaque 12 will not be in a state that poses a risk to the subject by determining that the plaque 12 will not be in a state that obstructs the blood flow in the blood vessel 11.

If the plaque 12 is in a state that poses a risk to the subject (step S107: Yes), the display control function 155e proceeds to step S109 and executes the processing of step S109. On the other hand, if the plaque 12 is not in a state that poses a risk to the subject (step S107: No), the calculation function 155c proceeds to step S108 and executes the processing of step S108.

Therefore, in the third embodiment, the calculation function 155c calculates the WSS of the plaque 12 at time _Tk each time the time _Tk is derived, until the plaque 12 obstructs the blood flow in the blood vessel 11. Then, the prediction function 155d predicts the shape of the plaque 12 at the time Tk+1 next to the time _Tk , based on the calculated WSS each time the WSS of the plaque 12 is calculated at time _Tk , until the plaque 12 obstructs the blood flow in the blood vessel 11. Then, the display control function 155e causes the display 154 to display the shape of the plaque 12 at time _{Tk+1 ,} when the plaque 12 obstructs the blood flow in the blood vessel 11.

The above describes the analysis device 150 and analysis system 100 according to the third embodiment. According to the third embodiment, it is possible to predict that in the relatively distant future, plaque 12 will reach a state where it poses a risk to the subject. It is also possible to predict that in the relatively distant future, plaque 12 will reach a state where it obstructs blood flow in the blood vessel 11.

Furthermore, according to the third embodiment, it is possible to allow a user such as a doctor to confirm that in the relatively distant future, plaque 12 will reach a state where it will pose a risk to the subject. Furthermore, according to the third embodiment, it is possible to allow a user such as a doctor to confirm that in the relatively distant future, plaque 12 will reach a state where it will obstruct blood flow in blood vessel 11. As a result, it is possible to support the diagnosis and formulation of treatment plans for diseases of blood vessels such as coronary arteries, which are performed by users such as doctors.

(Fourth embodiment)
In the first embodiment, the analysis device 150 predicts the shape of the plaque 12 at the time T _N+1 when the plaque 12 reaches a specific state in a state where a therapeutic stent is not placed in the blood vessel 11. However, the analysis device 150 may further predict the shape of the plaque 12 at the time T _N+1 when the plaque 12 reaches a specific state in a state where a therapeutic stent is placed in the blood vessel 11. Then, the analysis device 150 may display the shape of the plaque 12 predicted in a state where a stent is not placed in the blood vessel 11 and the shape of the plaque 12 predicted in a state where a stent is placed in the blood vessel 11. Thus, such an embodiment will be described as a fourth embodiment.

Note that in the description of the fourth embodiment, differences from the first embodiment will be mainly described, and descriptions of configurations similar to those of the first embodiment may be omitted. For example, in the description of the fourth embodiment, configurations similar to those of the first embodiment may be given the same reference numerals, and descriptions of configurations similar to those of the first embodiment may be omitted.

In the fourth embodiment, similarly to the first embodiment, the analysis device 150 first predicts the shape of the plaque 12 at time T _N+1 when the plaque 12 reaches a specific state in a state where no stent is placed in the blood vessel 11. In the following description of the fourth embodiment, the "state where no stent is placed in the blood vessel 11" will be referred to as the "first state." For example, the analysis device 150 predicts the shape of the plaque 12 at time T _N+1 when the plaque 12 reaches a specific state in the first state by executing each process of steps S101 to S108 shown in FIG.

FIG. 12 is a diagram for explaining an example of a process executed by the analysis device 150 according to the fourth embodiment. In the example of FIG. 12, a case where a stent treatment is performed is shown. As shown in FIG. 12, a narrowed portion of a blood vessel 11 narrowed by a plaque 12 is widened by a stent 14. The analysis device 150 further predicts the shape of the plaque 12 at a time T _N+1 when the plaque 12 becomes a specific state in a state where the stent 14 is placed in the blood vessel 11 as shown in FIG. 12. In the description of the fourth embodiment, the "state where the stent 14 is placed in the blood vessel 11" is hereinafter referred to as a "second state". For example, the analysis device 150 predicts the shape of the plaque 12 at a time T _N+1 when the plaque 12 becomes a specific state in the second state by executing a process similar to the processes of steps S101 to S108 shown in FIG. 2. However, in step S104, the calculation function 155c calculates the WSS for the plaque 12 at time T _N based on the shape of the blood vessel 11 at time T ₀ and the shape of the plaque 12 at time T _N as well as the shape of the stent 14. The shape of the stent 14 is constant at all times in the analysis process and does not change.

Fig. 13 is a diagram for explaining an example of processing executed by the analysis device 150 according to the fourth embodiment. As shown in Fig. 13, the display control function 155e causes the display 154 to display, side by side, the shape of the plaque 12 at the time T _N+1 when the plaque 12 becomes a specific state in the first state and the shape of the plaque 12 at the time T _N+1 when the plaque 12 becomes a specific state in the second state. This allows a user such as a doctor to confirm the predicted result of the shape of the plaque 12 when stent treatment using the stent 14 is performed and the predicted result of the shape of the plaque 12 when stent treatment is not performed. As a result, it is possible to support the diagnosis of a disease of a blood vessel such as a coronary artery, the formulation of a treatment plan, etc., performed by a user such as a doctor.

Also, as shown in FIG. 13, the display control function 155e causes the position "P1" of the stent 14 and the length "L1" of the stent 14 to be displayed on the display 154. This allows a user such as a doctor to confirm the position and length of the stent 14 used during stent treatment. Therefore, this also supports the diagnosis and formulation of treatment plans for diseases of blood vessels such as coronary arteries performed by users such as doctors.

Furthermore, the display control function 155e may display on the display 154 the time T _N+1 at which the plaque 12 becomes a specific state in the first state and the time T _N+1 at which the plaque 12 becomes a specific state in the second state. The time T _N+1 at which the plaque 12 becomes a specific state in the first state and the time T _N+1 at which the plaque 12 becomes a specific state in the second state may be the same time or different time. This allows a user such as a doctor to confirm the time at which the plaque 12 becomes a specific state in each of the first state and the second state. Therefore, from this point of view, it is possible to support the diagnosis of a disease of a blood vessel such as a coronary artery, the formulation of a treatment plan, etc., performed by a user such as a doctor.

In the fourth embodiment, the time when the plaque 12 reaches a specific state is, for example, the time when the growth of the plaque 12 converges, or the time when the plaque 12 reaches a state where it poses a risk to the subject (for example, the time when the plaque 12 ruptures or the time when the plaque 12 obstructs blood flow in the blood vessel 11).

Here, in the fourth embodiment, the time point at which the plaque 12 becomes a specific state may be, for example, a specific time point at which the plaque 12 becomes plaque at a specific time point a predetermined time (e.g., several years) after the time point T _0. Such a specific time point is an example of the third time point.

The above describes the analysis device 150 and analysis system 100 according to the fourth embodiment. As described above, the fourth embodiment can assist users such as doctors in making diagnoses and formulating treatment plans for diseases of blood vessels such as coronary arteries.

Fifth Embodiment
In the fourth embodiment, a case has been described in which the analysis device 150 displays a predicted result of the shape of the plaque 12 when stent treatment using the stent 14 is performed, and a predicted result of the shape of the plaque 12 when stent treatment is not performed. However, the analysis device 150 may display a predicted shape of the plaque 12 in each of a plurality of states in which the stent 14 is placed in the blood vessel 11, the states differing from each other in at least one of the position and the length of the stent 14 placed in the blood vessel 11. Thus, such an embodiment will be described as a fifth embodiment.

Note that in the description of the fifth embodiment, differences from the fourth embodiment will be mainly described, and descriptions of configurations similar to those of the fourth embodiment may be omitted. For example, in the description of the fifth embodiment, configurations similar to those of the fourth embodiment may be given the same reference numerals, and descriptions of configurations similar to those of the fourth embodiment may be omitted.

In the fifth embodiment, the analysis device 150 predicts the shape of the plaque 12 at time T N+1 when the plaque 12 becomes a specific state in each of a plurality of states in which the _stent 14 is placed in the blood vessel 11, in a manner similar to that of the fourth embodiment. These plurality of states are a plurality of states in which at least one of the position and the length of the stent 14 placed in the blood vessel 11 is different from each other. In the following, two states will be described as an example of the plurality of states, but the plurality of states may be three or more states.

For example, two states will be described: a state in which a stent 14 having a length of "L2" is placed at a position "P2" in the blood vessel 11, and a state in which a stent 14 having a length of "L3" is placed at a position "P3" in the blood vessel 11. In this case, the analysis device 150 predicts the shape of the plaque 12 at the time T _N+1 when the plaque 12 reaches a specific state in each of these two states.

In the following description of the fifth embodiment, the state in which a stent 14 having a length of "L2" is placed at a position "P2" in the blood vessel 11 is referred to as the "first state." In the following description of the fifth embodiment, the state in which a stent 14 having a length of "L3" is placed at a position "P3" in the blood vessel 11 is referred to as the "second state."

14 is a diagram for explaining an example of a process executed by the analysis device 150 according to the fifth embodiment. As shown in FIG. 14, the display control function 155e causes the display 154 to display the shape of the plaque 12 at the time T _N+1 when the plaque 12 becomes a specific state in the first state and the shape of the plaque 12 at the time T _N+1 when the plaque 12 becomes a specific state in the second state side by side. Note that the time T _N+1 when the plaque 12 becomes a specific state in the first state and the time T _N+1 when the plaque 12 becomes a specific state in the second state may be the same time or different time. This allows a user such as a doctor to confirm the predicted result of the shape of the plaque 12 when stent treatment is performed in the first state and the predicted result of the shape of the plaque 12 when stent treatment is performed in the second state. As a result, it is possible to support the diagnosis of a disease of a blood vessel such as a coronary artery, the formulation of a treatment plan, etc., performed by a user such as a doctor.

Also, as shown in FIG. 14, the display control function 155e causes the position "P2" of the stent 14 and the length "L2" of the stent 14, as well as the position "P3" of the stent 14 and the length "L3" of the stent 14, to be displayed on the display 154.

Here, in the fifth embodiment, the time point at which the plaque 12 reaches a specific state may be, for example, a specific time point at which the plaque 12 becomes plaque at a specific time point a predetermined time (e.g., several years) after the time point _T0 . Such a specific time point is an example of the third time point. In this case, the display control function 155e may cause the display 154 to display, among the shapes of the multiple plaques 12 at the specific time point, the shape of the plaque 12 that does not pose a risk to the subject.

The above describes the analysis device 150 and analysis system 100 according to the fifth embodiment. As described above, the fifth embodiment can assist users such as doctors in making diagnoses and formulating treatment plans for diseases of blood vessels such as coronary arteries.

Sixth Embodiment
In the first embodiment, the subject is not administered with a drug that reduces cholesterol levels in the blood, such as a statin or a PCSK9 inhibitor. Therefore, in the first embodiment, the analysis device 150 predicts the shape of the plaque 12 at the time T _N+1 when the plaque 12 becomes a specific state when no drug is administered. However, the analysis device 150 may further predict the shape of the plaque 12 at the time T _N+1 when the plaque 12 becomes a specific state when the subject is administered with the above-mentioned drug. Then, the analysis device 150 may display the shape of the plaque 12 predicted when no drug is administered to the subject and the shape of the plaque 12 predicted when the drug is administered to the subject. Therefore, such an embodiment will be described as a sixth embodiment.

In the description of the sixth embodiment, differences from the first embodiment will be mainly described, and descriptions of configurations similar to those of the first embodiment may be omitted. For example, in the description of the sixth embodiment, configurations similar to those of the first embodiment may be given the same reference numerals, and descriptions of configurations similar to those of the first embodiment may be omitted.

In the sixth embodiment, similarly to the first embodiment, the analysis device 150 first predicts the shape of the plaque 12 at time T _N+1 when the plaque 12 becomes a specific state in a state in which no drug is administered to the subject. In the following description of the sixth embodiment, the "state in which no drug is administered to the subject" will be referred to as the "first state." For example, the analysis device 150 predicts the shape of the plaque 12 at time T _N+1 when the plaque 12 becomes a specific state in the first state by executing each process of steps S101 to S108 shown in FIG.

The analysis device 150 further predicts the shape of the plaque 12 at time T _N+1 when the plaque 12 becomes a specific state in a state in which the drug has been administered to the subject. In the description of the sixth embodiment, the "state in which the drug has been administered to the subject" will be referred to as the "second state". For example, the analysis device 150 predicts the shape of the plaque 12 at time T _N+1 when the plaque 12 becomes a specific state in the second state by executing the same processes as the processes of steps S101 to S108 shown in FIG. However, in step S105, the prediction function 155d takes into account the influence according to the type and dosage of the drug, etc., when predicting the shape of the plaque 12.

FIG. 15 is a diagram for explaining an example of a process executed by the analysis device 150 according to the sixth embodiment. As shown in FIG. 15, the display control function 155e causes the display 154 to display the shape of the plaque 12 at the time T _N+1 when the plaque 12 becomes a specific state in the first state and the shape of the plaque 12 at the time T _N+1 when the plaque 12 becomes a specific state in the second state side by side. Note that the time T _N+1 when the plaque 12 becomes a specific state in the first state and the time T _N+1 when the plaque 12 becomes a specific state in the second state may be the same time or different time. This allows a user such as a doctor to confirm the predicted result of the shape of the plaque 12 when a drug treatment is performed and the predicted result of the shape of the plaque 12 when a drug treatment is not performed. As a result, it is possible to support the diagnosis of a disease of a blood vessel such as a coronary artery, the formulation of a treatment plan, etc., performed by a user such as a doctor.

Also, as shown in FIG. 15, the display control function 155e causes the type of drug "K1" administered to the subject and the drug dosage "D1" to be displayed on the display 154. This allows a user such as a doctor to confirm the type and dosage of the drug used during drug treatment. Therefore, this also supports the diagnosis and formulation of treatment plans for diseases of blood vessels such as coronary arteries performed by users such as doctors.

The display control function 155e may also cause the display 154 to display the time T _N+1 at which the plaque 12 becomes a specific state in the first state and the time T _N+1 at which the plaque 12 becomes a specific state in the second state.

In the sixth embodiment, the point in time when the plaque 12 reaches a specific state is, for example, the same as in the fourth embodiment.

The above describes the analysis device 150 and analysis system 100 according to the sixth embodiment. As described above, the sixth embodiment can assist users such as doctors in making diagnoses and formulating treatment plans for diseases of blood vessels such as coronary arteries.

Seventh Embodiment
In the sixth embodiment, the analysis device 150 displays the predicted shape of the plaque 12 when drug treatment is performed and the predicted shape of the plaque 12 when drug treatment is not performed. However, the analysis device 150 may display the predicted shape of the plaque 12 in each of a plurality of states in which a drug is administered to the subject, the states being different from each other in at least one of the type and the dosage of the drug administered to the subject. Therefore, such an embodiment will be described as the seventh embodiment.

In the description of the seventh embodiment, differences from the sixth embodiment will be mainly described, and descriptions of configurations similar to those of the sixth embodiment may be omitted. For example, in the description of the seventh embodiment, configurations similar to those of the sixth embodiment may be given the same reference numerals, and descriptions of configurations similar to those of the sixth embodiment may be omitted.

In the seventh embodiment, the analysis device 150 predicts the shape of the plaque 12 at time T N+1 when the _plaque 12 becomes a specific state in each of a plurality of states in which a drug is administered to a subject, using a method similar to that of the sixth embodiment. The plurality of states are a plurality of states in which at least one of the type of drug administered to the subject and the dosage of the drug is different from each other. In the following, two states will be described as an example of the plurality of states, but the plurality of states may be three or more states.

For example, two states will be described below: a state where a drug of type "K2" is administered to a subject at a dose "D2", and a state where a drug of type "K3" is administered to a subject at a dose "D3". In the seventh embodiment, the analysis device 150 predicts the shape of the plaque 12 at time T _N+1 when the plaque 12 becomes a specific state in each of the two states.

In the following description of the seventh embodiment, the state in which a drug of type "K2" is administered to a subject in a dose of "D2" is referred to as the "first state." In the following description of the seventh embodiment, the state in which a drug of type "K3" is administered to a subject in a dose of "D3" is referred to as the "second state."

FIG. 16 is a diagram for explaining an example of a process executed by the analysis device 150 according to the seventh embodiment. As shown in FIG. 16, the display control function 155e causes the display 154 to display the shape of the plaque 12 at the time T _N+1 when the plaque 12 becomes a specific state in the first state and the shape of the plaque 12 at the time T _N+1 when the plaque 12 becomes a specific state in the second state side by side. Note that the time T _N+1 when the plaque 12 becomes a specific state in the first state and the time T _N+1 when the plaque 12 becomes a specific state in the second state may be the same time or different time. This allows a user such as a doctor to confirm the predicted result of the shape of the plaque 12 when a drug treatment is performed in the first state and the predicted result of the shape of the plaque 12 when a drug treatment is performed in the second state. As a result, it is possible to support the diagnosis of a disease of a blood vessel such as a coronary artery, the formulation of a treatment plan, etc., performed by a user such as a doctor.

Also, as shown in FIG. 16, the display control function 155e causes the drug type "K2" and drug dosage "D2", as well as the drug type "K3" and drug dosage "D3" to be displayed on the display 154.

In the seventh embodiment, the time when the plaque 12 becomes a specific state is, for example, the same as in the sixth embodiment. For example, in the seventh embodiment, the time when the plaque 12 becomes a specific state is, for example, a specific time when the plaque 12 becomes a specific plaque a predetermined time after the time _T0 (for example, several years later, etc.). In this case, the display control function 155e may cause the display 154 to display, among the shapes of the multiple plaques 12 at the specific time, the shape of the plaque 12 that does not pose a risk to the subject.

The above describes the analysis device 150 and analysis system 100 according to the seventh embodiment. As described above, the seventh embodiment can assist users such as doctors in making diagnoses and formulating treatment plans for diseases of blood vessels such as coronary arteries.

Other Embodiments
In the above-mentioned embodiment and modified example, an example in which CT image data is used as medical image data has been described, but the embodiment is not limited thereto. For example, any type of medical image data may be used as long as it is a type of medical image data from which the shape of blood vessels and the shape of plaque can be extracted. For example, ultrasound image data obtained by an ultrasound diagnostic image, MR image data obtained by an MRI device, etc. may be used.

The term "processor" used in the description of the above-mentioned embodiment means, for example, a circuit such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an Application Specific Integrated Circuit (ASIC), a programmable logic device (for example, a Simple Programmable Logic Device (SPLD), a Complex Programmable Logic Device (CPLD), and a Field Programmable Gate Array (FPGA)). Here, instead of storing a program in the memory circuit 152, the program may be directly embedded in the processor circuit. In this case, the processor realizes its function by reading and executing the program embedded in the circuit. In addition, each processor is not limited to being configured as a single circuit for each processor, and may be configured as a single processor by combining multiple independent circuits to realize its function.

Here, the program executed by the processor is provided in advance in a ROM (Read Only Memory) or a storage circuit. The program may be provided in a format that can be installed in these devices or in a format that can be executed, recorded on a non-transient storage medium that can be read by a computer, such as a CD (Compact Disk)-ROM, a FD (Flexible Disk), a CD-R (Recordable), or a DVD (Digital Versatile Disk). The program may also be provided or distributed by being stored on a computer connected to a network, such as the Internet, and downloaded via the network. For example, the program is composed of modules including each of the above-mentioned processing functions. In terms of actual hardware, the CPU reads and executes the program from a storage medium, such as a ROM, so that each module is loaded onto a main storage device and generated on the main storage device.

In addition, in the above-mentioned embodiment and modified examples, each component of each device shown in the figures is a functional concept, and does not necessarily have to be physically configured as shown in the figures. In other words, the specific form of distribution or integration of each device is not limited to that shown in the figures, and all or part of it can be functionally or physically distributed or integrated in any unit depending on various loads, usage conditions, etc. Furthermore, each processing function performed by each device can be realized in whole or in any part by a CPU and a program analyzed and executed by the CPU, or can be realized as hardware using wired logic.

Furthermore, among the processes described in the above-mentioned embodiments and variations, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically using known methods. In addition, the information including the processing procedures, control procedures, specific names, various data, and parameters shown in the above documents and drawings can be changed as desired unless otherwise specified.

According to at least one embodiment or at least one modified example described above, it is possible to predict the state of plaque in the relatively distant future.

Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are within the scope of the invention and its equivalents as set forth in the claims, as well as the scope and spirit of the invention.

100 Analysis system 150 Analysis device 153 Input interface 152a CT image data 154 Display 155 Processing circuit 155a Acquisition function 155b Extraction function 155c Calculation function 155d Prediction function 155e Display control function

Claims (19)

an extraction unit that extracts a shape of a blood vessel of a subject and a shape of plaque formed in the blood vessel from medical image data;
a calculation unit that calculates a mechanical index related to the plaque at a first time point based on a shape of the blood vessel and a shape of the plaque at the first time point while successively changing the first time point;
a prediction unit that predicts a shape of the plaque at a second time point subsequent to the first time point based on the mechanical index at the first time point;
a display control unit that causes a display unit to display the predicted shape of the plaque at the second time point when the plaque will be in a specific state; and
An analysis device comprising: the display control unit causes the display unit to display the predicted shape of the plaque at the second time point when the growth of the plaque converges.
The analysis device according to claim 1 . the display control unit causes the display unit to display the predicted shape of the plaque at the second time point when the plaque will become in a state that causes a risk to the subject.
The analysis device according to claim 1 . The display control unit causes the display unit to display the predicted shape of the plaque at the second time point when the plaque is in a ruptured state.
The analysis device according to claim 3. The display control unit causes the display unit to display the predicted shape of the plaque at the second time point when the plaque will obstruct blood flow in the blood vessel.
The analysis device according to claim 3. a receiving unit that receives at least one of an instruction to modify a shape of the blood vessel, an instruction to modify a first parameter related to blood flowing into the blood vessel, and an instruction to modify a second parameter related to blood flowing out of the blood vessel,
the calculation unit calculates the mechanical index based on at least one of the shape of the blood vessel corrected based on the at least one instruction received by the reception unit, the first parameter, and the second parameter;
The analysis device according to any one of claims 1 to 5. the prediction unit predicts the shape of the plaque at the second time point by making the shape of the plaque at the second time point larger than the shape of the plaque at the first time point when a magnitude of the shear stress applied to the plaque at the first time point indicated by the mechanical index at the first time point is below a first threshold value.
The analysis device according to any one of claims 1 to 6. the prediction unit predicts the shape of the plaque at the second time point by making the shape of the plaque at the second time point larger than the shape of the plaque at the first time point when the magnitude of the shear stress applied to the plaque at the first time point indicated by the mechanical index at the first time point is below a first threshold value and a maximum value of the difference of the shear stress in one beat exceeds a second threshold value.
The analysis device according to any one of claims 1 to 6. the prediction unit predicts the shape of the plaque at the second time point by enlarging the shape of the plaque by a predetermined size from each of a plurality of positions on the surface of the plaque at the first time point in a normal direction of each of the plurality of positions.
The analysis device according to claim 7 or 8. the prediction unit predicts the shape of the plaque at the second time point by enlarging the shape of the plaque from each of a plurality of positions on the surface of the plaque at the first time point in a normal direction of each of the plurality of positions by a magnitude corresponding to the magnitude of the shear stress.
The analysis device according to claim 7 or 8. the prediction unit predicts the shape of the plaque at the second time point by enlarging the shape of the plaque in a normal direction of each of a plurality of positions on the surface of the plaque at the first time point by a size corresponding to an angle between the normal direction of each of the plurality of positions and a direction in which blood flows in the blood vessel.
The analysis device according to claim 7 or 8. The prediction unit further sets a physical property of the plaque at the second time point such that the plaque at the second time point is harder than the plaque at the first time point when the magnitude of the shear stress is equal to or greater than the first threshold value.
The analysis device according to any one of claims 7 to 11. The prediction unit further sets a physical property of the plaque at the second time point such that the plaque at the second time point is softer than the plaque at the first time point when the magnitude of the shear stress is equal to or less than a third threshold value that is smaller than the first threshold value.
The analysis device according to any one of claims 7 to 12. the calculation unit calculates the mechanical index in each of a first state in which a stent is not placed in the blood vessel and a second state in which the stent is placed in the blood vessel;
The prediction unit predicts a shape of the plaque in each of the first state and the second state,
the display control unit causes the display unit to display the predicted shape of the plaque at the second time point when the plaque will become the specific state in the first state, and the predicted shape of the plaque at the second time point when the plaque will become the specific state in the second state.
The analysis device according to claim 1 . the calculation unit calculates the mechanical index in each of a plurality of states in which a stent is placed in the blood vessel, the states being different from each other in at least one of a position of the stent placed in the blood vessel and a length of the stent;
The prediction unit predicts a shape of the plaque in each of the plurality of states,
the display control unit causes the display unit to display the predicted shape of the plaque at the second time point when the plaque will be in the specific state in each of the plurality of states.
The analysis device according to claim 1 . The calculation unit calculates the mechanical index in each of a first state in which a drug is not administered to the subject and a second state in which the drug is administered to the subject;
The prediction unit predicts a shape of the plaque in each of the first state and the second state,
the display control unit causes the display unit to display the predicted shape of the plaque at the second time point when the plaque will become the specific state in the first state, and the predicted shape of the plaque at the second time point when the plaque will become the specific state in the second state.
The analysis device according to claim 1 . the calculation unit calculates the mechanical index in each of a plurality of states in which the drug is administered to the subject, the states being different from each other in at least one of a type of the drug administered to the subject and a dosage of the drug;
The prediction unit predicts a shape of the plaque in each of the plurality of states,
The display control unit causes the display unit to display a predicted shape of the plaque at the second time point when the plaque will be in the specific state in each of the plurality of states.
The analysis device according to claim 1 . 1. A processor-implemented analysis method, comprising:
Extracting the shape of the blood vessel of the subject and the shape of plaque formed in the blood vessel from the medical image data;
calculating a mechanical index for the plaque at a first time point based on the shape of the blood vessel and the shape of the plaque at the first time point while successively changing the first time point;
predicting a shape of the plaque at a second time point subsequent to the first time point based on the mechanical index at the first time point;
displaying on a display unit the predicted shape of the plaque at the second time point when the plaque will be in a specific state;
The analysis method includes: An analysis system including a medical image diagnostic device and an analysis device,
The medical image diagnostic apparatus includes:
A generating unit generates medical image data in which a blood vessel of a subject and plaque formed in the blood vessel are depicted,
The analysis device includes:
An acquisition unit that acquires the medical image data;
an extraction unit that extracts a shape of a blood vessel of a subject and a shape of plaque formed in the blood vessel from the medical image data;
a calculation unit that calculates a mechanical index related to the plaque at a first time point based on a shape of the blood vessel and a shape of the plaque at the first time point while successively changing the first time point;
a prediction unit that predicts a shape of the plaque at a second time point subsequent to the first time point based on the mechanical index at the first time point;
and a display control unit that causes a display unit to display the predicted shape of the plaque at the second time point when the plaque is in a specific state.
Analysis system.

Images